Ghorbani, Houman2025-07-222025-07-222025-07-22http://hdl.handle.net/10393/50682https://doi.org/10.20381/ruor-31262The thesis is based on an industry project offered to our research laboratory. The industry required the feasibility evaluation of designing a spectrometer that scans the C-band (1530 – 1565 nm) with a resolution of lower than 1 GHz, has a scanning speed of at least 10 Hz, a maximum occupied area of 10 square centimeters, and a maximum consumed power of 3 watts. A compact integrated solution to fulfill the requirements was considered. The ring resonator and arrayed waveguide grating (AWG) were selected as the fine and coarse filter, respectively; being the main components of the spectrometer. Among different integrated platforms silicon nitride was chosen because of its relatively low loss performance and small footprint compared to other available platforms. The ring resonator needs to have a resolution of lower than 1 GHz and be tunable over its free spectral range (FSR) to scan the whole C-band. The AWG on the other hand needs to separate the individual resonant frequencies that exit the ring resonator. Conventional AWGs have bell-shaped channel profiles and cannot achieve flat output responses for varied input frequency. Thus, the incoherent weighted summation technique was used to construct virtual channel profiles (VCP) from AWG channel profiles to attain a flat on-resonance frequency response over the C-band. This method requires the ring resonator FSR to be as large as possible relative to AWG channel spacing, and the AWG channel profiles have overlapping passbands that intersect sufficiently above noise level, to achieve desired crosstalk performance. After choosing the right method and finding out performance requirements for the ring resonator and AWG, the feasibility of designing a silicon nitride ring resonator to have a resolution of lower than 1 GHz was evaluated. This step includes bend simulation to acquire the minimum bend radius, transmission simulations to know the right power coupling ratio to achieve a resolution of lower than 1 GHz and determining the minimum gap size in the ring coupler region. Next, the thermal tunability of the ring resonator was assessed by simulation to determine maximum tunable FSR of the ring resonator, its consumed power, and scanning speed. In the following, based on the requirements imposed by the incoherent weighted summation method, and known maximum tunable ring resonator FSR, design specifications for the AWG were determined, and the feasibility of designing the target AWG was evaluated by simulation. Finally, the combined performance of the ring resonator and AWG was simulated to evaluate the spectrometer as a whole. The industry requirements for the spectrometer including the frequency range, resolution, consumed power, scanning speed, and area are met. The scanning of the C-band with a resolution of lower than 1 GHz significantly beefs up the capacity of the band by allowing the use of a huge number of channels and the effective monitoring of the band to use empty channels or replace damaged ones.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Photonic Integrated CircuitsRing ResonatorArrayed Waveguide GratingSilicon NitrideThesis